Interview With The Vampire || Exit Music (For A Film) 

It’s highly likely that Armand is messing with Louis’ mind in the present day and he has yet to realize Armand was responsible for her death yet

Actually Louis was with Armand in the books for a while.

They kill her not for being a child but because she killed her maker. Supposedly. You say the writers of the show didn't read the books but when Armand confesses to Louis that he was involved in Claudia's death, Louis says he already knew it, and despite that he spent many years by his side. I wasn't sure about the changes on the series at first, but if you actually did read the books, you'll know that said changes don't modify the characters' core

As it's been already mentioned, Louis stays with Armand for decades in the books knowing that he had more than a small part in Claudia's death. Don't underestimate Louis' capacity for loving terrible people, it's kind of his thing

I'm actually curious myself if you read the books? Armand was presented as even worse than Lestat in the first book, the rest of the books gives more nuance to all the characters and everyone becomes even more villainous. I'm loving this re-interpretation of the books because as much as I loved them, AR was a terribly inconsistent writer and the show is leaning on that as a way to comment on the monster that is memory, how the truth will never be fully known because every single character perceived it differently, and changed the events for some reason, everyone is an unreliable narrator. Book!Louis failed Claudia horribly, but him staying with Armand was classic dissociation, what he always does, and passive aggressiveness as well. Armand, Lestat and Louis have the most complicated relationship